MOSCOW (Reuters) -- Russian President Dmitry Medvedev could resign from his post in 2009 to pave the way for Vladimir Putin to return to the Kremlin, "Vedomosti" newspaper has reported, citing an unidentified source close to the Kremlin.

Medvedev on November 5 proposed increasing the presidential term to six years from four years, a step the newspaper said was part of a plan drawn up by Vladislav Surkov, who serves as Medvedev's first deputy chief of staff.

Under the plan, Medvedev could implement changes to the constitution and unpopular social reforms "so that Putin could return to the Kremlin for a longer period," the newspaper said.

"Under this scenario Medvedev could resign early citing changes to the constitution and then presidential elections could take place in 2009," the newspaper said, citing the unidentified source close to the Kremlin.

The paper said Putin, who is currently prime minister, could then rule for two six year terms, so from 2009 to 2021. The paper cited Putin's spokesman as saying he saw no reason for Putin to return to power in 2009.

Investors, already jittery over the impact of the financial crisis on Russia's economic boom, are trying to work out who is really in charge of Russia, the biggest question for those seeking to ascertain political risk.

They are seeking any details on how the current set up -- with Medvedev as president and Putin as prime minister -- could change. During Medvedev's speech on November 5 the Russian stock market erased most of the gains it made earlier in the day.